Pharmacological Approaches Increasing Thermal Radiosensi

该项目将检验这样一种假设，即高温导致特定的细胞和/或核变化，使细胞对电离辐射敏感。这一假设的一个推论是，引起与热相同变化的化学或物理因素也会导致细胞对辐射敏感。建立这一假说及其推论为这一项目提供了基础：识别和开发诱导辐射敏化的药理制剂 利用与热休克相同的分子途径，可用于增强中等热疗的放射增敏效应。 目的1：验证蛋白质在核内聚集可增加辐射敏感性的假设。为了实现这一目标，我们将使用稳定转染载体的细胞，这些载体有条件地表达GFP融合蛋白，这些融合蛋白被设计为自发聚集在细胞核或胞浆中。 目的2：寻找增强热疗放射增敏作用的药理物质。非甾体抗炎药吲哚美辛是我们的起始化合物。以往的工作已经证实，吲哚美辛可以作为放射增敏剂和热放射增敏的增强剂。另一项独立的工作表明，吲哚美辛降低了热诱导蛋白质聚集所需的温度，并降低了HSF-1激活所需的温度，因此，在本身不足以激活的温度下，可以获得完整的热休克反应。 目的3)确定具有热放射增敏作用的伊洛尔类似物的结构特征。将合成吲哚美辛类似物，并进行结构-功能分析，以最大限度地增强活性并将毒性降至最低。模拟设计将基于AIMS 1和2中确定的分子决定物。也就是说，我们将识别和设计具有优化的结构特征的类似物，以导致蛋白质聚集、DNA传感器功能抑制和NADPH氧化酶活性的激活。目的4：确定AIM 3中确定的吲哚美辛类似物是否增强体内的热放射增敏作用。 将使用两种人体异种移植肿瘤模型(NSY和HT-29)。测试将由体内程序核心执行。选择类似物的标准将基于在AIM 3中进行的体外试验的结果。在促进活性方面最有效、毒性最小、对环氧合酶-1和-2抑制最小的类似物将在体内进行测试。

This project will test the hypothesis that hyperthermia induces specific cellular and/or nuclear changes that sensitize cells to ionizing radiation. A corollary of this hypothesis is that chemical or physical agents that induce the same changes as heat will also cause cells to become radiosensitive. Establishing this hypothesis and its corollary provide the basis of this project: the identification and development of pharmacological agents that induce radiation sensitization utilizing the same molecular pathways as heat shock and can be used to enhance the radiosensitizing effects of moderate hyperthermia. Aim 1: Test the hypothesis that radiation sensitivity can be increased by the aggregation of proteins in the nucleus. To accomplish this aim, we will use cells stably transfected with vectors that conditionally express GFPfusion proteins engineered to spontaneously aggregate in the nucleus or in the cytosol. Aim 2: Identify pharmacological agents that enhance hyperthermic radiosensitization. The NSAID indomethacin is our starting compound. Previous work has established that indomethacin can act a radiosensitizer and enhancer of thermal radiosensitization. Other, independent work, has shown that indomethacin lowers the temperature necessary for the heat induced protein aggregation and lowers the temperature necessary for Hsf-1 activation, such that a complete heat shock response can be attained at temperatures that are by themselves, insufficient for activation. Aim 3) Determine the structural features of inflole analogs that confer thermal radiosensitization. Indomethacin analogs will be synthesized and subjected to a structure-function analysis in order to maximize enhancer activity and minimize toxicity. Analog design will be based on the molecular determinates identified in Aims 1 and 2. That is, we will identify and design analogs with structural features optimized to cause protein aggregation, DNA sensor function inhibition and activation ofNADPH oxidase activity. Aim 4: Determine if the indomethacin analogs identified in Aim 3 enhance thermal radiosensitization in vivo. Two human xenograph tumor models (NSY and HT-29 will be used. Testing will be performed by the in vivo procedures core. The criteria for analog selection will be based on the results obtained from the in vitro performed in Aim 3. Analogs that are the most efficacious in terms of enhancer activity, the least toxic, and exhibit minimal inhibition of cyclooxygenase -1 and -2 will be tested in vivo.